Daily Archives: January 4, 2012

Reality Check: Have tornados increased?

The claim is made that extreme weather events have and will increase due to global warming. The recent EPA/CA guide to regional water planning (click here) states “As the climate warms, extreme events are expected to become more frequent…”

The AWWA Climate Change Committee (AWWA Journal, July 2011, page 42):

 “Extreme weather events have increased, and regional climate patterns are changing.”

Below is the historical record with regard to tornados. This historical record does not support the above statements with regard to increasing extreme weather events, at least for EF3-EF5 tornados.

Source: Real-Science

Levy and Leclerc 2011: Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents

Levy, M. and B.S. Leclerc. 2011. Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents. Cancer Epidemiol. Dec 19.


INTRODUCTION: It has been suggested that fluoride in drinking water may increase the risk of osteosarcoma in children and adolescents, although the evidence is inconclusive. We investigated the association between community water fluoridation (CWF) and osteosarcoma in childhood and adolescence in the continental U.S.

METHODS: We used the cumulative osteosarcoma incidence rate data from the CDC Wonder database for 1999-2006, categorized by age group, sex and states. States were categorized as low (≤30%) or high (≥85%) according to the percentage of the population receiving CWF between 1992 and 2006. Confidence intervals for the incidence rates were calculated using the Gamma distribution and the incidence rates were compared between groups using Poisson regression models.

RESULTS: We found no sex-specific statistical differences in the national incidence rates in the younger groups (5-9, 10-14), although 15-19 males were at higher risk to osteosarcoma than females in the same age group (p<0.001). Sex and age group specific incidence rates were similar in both CWF state categories. The higher incidence rates among 15-19 year old males vs females was not associated with the state fluoridation status. We also compared sex and age specific osteosarcoma incidence rates cumulated from 1973 to 2007 from the SEER 9 Cancer Registries for single age groups from 5 to 19. There were no statistical differences between sexes for 5-14 year old children although incidence rates for single age groups for 15-19 year old males were significantly higher than for females.

CONCLUSION: Our ecological analysis suggests that the water fluoridation status in the continental U.S. has no influence on osteosarcoma incidence rates during childhood and adolescence.

Click here for the full paper (fee).